#! /bin/bash
# after-dirvish, a tool for copying certain Dirvish logs, etc. to local storage
# (from an external/removable device mounted on the bank directory)
# Version 1.1
#
# Usage: after-dirvish <uuid> <desc>
#
# Directory structure within /var/log/dirvish (bank name is ignored):
#   <vault>
#     summary
#     <UUID>
#       drive_desc.txt
#       index.gz
#       <image>.log
#       <older_image>.log.gz
#       <even_older_image>.log.gz
#     <UUID>
#       ...
#   <vault>
#     ...
#
#
# Copyright (C) 2011 Alastair Irvine <alastair@plug.org.au>
# Warpspace IT <http://www.warpspace.net/>
# 
#     This program is free software; you can redistribute it and/or modify
#     it under the terms of the GNU General Public License as published by
#     the Free Software Foundation; either version 2 of the License, or
#     (at your option) any later version.
# 
# On Debian systems, the complete text of the GNU General Public License
# can be found in `/usr/share/common-licenses/GPL'.


old_log_limit=2  # number of log files to keep around (other than the current one)
log_dir=/var/log/dirvish
DIRVISH_CONFIG=/etc/dirvish/master.conf

# extract the bank directory from the master config file and print it
# (whether or not it is on the same line as the Bank statement)
extract_bank_dir()
{
  awk 'BEGIN { bankline = -1 }
       tolower($1) == "bank:" { if (NF == 1) bankline = NR + 1; else print $2; }
       NR == bankline { print $1; }' $DIRVISH_CONFIG
}

# extract the vault names from the master config file and print them
# (whether or not they are on the same line as the Runall statement)
extract_active_vaults()
{
  awk 'BEGIN { print_it = 0 }
       /^[^\t ]/ || /^$/ { print_it = 0; }  # stop printing once a keyword or blank line is found
       print_it && !/^#/ { print $1; }      # print the line before the flag is turned on to avoid printing the Runall: keyword
       tolower($1) == "runall:" { 
                                  # look for vault names after Runall statement
                                  value = substr($0, 8); match_pos = match(value, /[^#]*/);
                                  names = substr(value, match_pos, RLENGTH);
                                  if (match_pos > 0 && match(names, /[^ \t]/) > 0)
                                    print names;
                                  else  # otherwise vault name(s) are on subsequent lines
                                    print_it = 1;
                                }' $DIRVISH_CONFIG
}


# *** MAINLINE ***
# == command-line handling ==
# (no options supported)
# process args
case ${#*} in
  0) echo after-dirvish: No UUID specified >&2
     exit 1
     ;;
  1) uuid=$1
     desc=None
     ;;
  *) uuid=$1
     shift
     desc="$*"
esac

# == Sanity checking ==
bank_dir=`extract_bank_dir`
## echo $bank_dir
if [ -z $bank_dir ] ; then
  echo after-dirvish: No Bank defined >&2
  exit 2
fi
if [ ! -d $bank_dir ] ; then
  echo after-dirvish: Bank not found >&2
  exit 3
fi
if [ -z "`ls $bank_dir`" ] ; then
  echo after-dirvish: Bank is empty >&2
  exit 4
fi
current_bank=${bank_dir##*/}

if [ "`echo $bank_dir/*/dirvish`" = $bank_dir/'*/dirvish' ] ; then
  echo after-dirvish: No vaults found in bank directory $bank_dir >&2
  exit 5
fi

# == Processing ==
process_vault()
{
  local vault_dir=$1 vault=$2
  local histfile=$vault_dir/dirvish/default.hist
  # logging info for $vault in $current_bank
  local last_image_name=`sed -n '$ s/\t.*//p' $histfile`
  if [ -z $last_image_name ] ; then
    echo "after-dirvish: Warning: no image found on last line of '$histfile'" >&2
    return 3
  fi
  local image_dir=$vault_dir/$last_image_name
  if [ ! -d $image_dir ] ; then
    echo "after-dirvish: Warning: image '$image_dir' not found" >&2
    return 4
  fi

  local vault_log_dir=$log_dir/$vault
  ## echo processing $vault_log_dir ; return
  mkdir -p $vault_log_dir

  # only copy the stuff from the image dir if this vault has a new image
  # i.e. there is no <image>.log for the mounted drive already in $vault_log_dir
  local dest_log_file=$vault_log_dir/$uuid/$last_image_name.log
  if [ ! -f $dest_log_file ] ; then
    # == update the summary file in the vault's log dir (include UUID) ==
    mv $vault_log_dir/summary $vault_log_dir/summary.bak 2> /dev/null
    # fail if the file isn't writable
    set -e
    touch $vault_log_dir/summary
    set +e
    # create a new one
    (echo filesystem: $uuid
     if [ "$desc" != None ] ; then echo "($desc)" ; fi 
     echo ; cat $image_dir/summary) > $vault_log_dir/summary

    # == store stuff for the mounted drive into the appropriate log subdir ==
    mkdir -p $vault_log_dir/$uuid

    cp -p $histfile $vault_log_dir/$uuid

    # -- copy and rotate the log files from the image dir --
    local files=(`ls -t $vault_log_dir/$uuid/*.log.gz 2>/dev/null`)
    if [ ${#files[*]} -ge $old_log_limit ] ; then
      local oldest_file=${files[${#files[*]}-1]} 
      rm $oldest_file
    fi

    # should only be one existing log file without a .gz extension; 
    # archive and replace it with a "copy" of the new log file
    gzip $vault_log_dir/$uuid/*.log 2>/dev/null
    if [ -r $image_dir/log ] ; then
      cp -p $image_dir/log $dest_log_file
    else
      zcat $image_dir/log.gz > $dest_log_file
    fi

    # -- copy the rest of the stuff from the image dir and add other stuff --
    (echo "$desc" ; df -m $vault_dir ) > $vault_log_dir/$uuid/drive_desc.txt
    ## readlink --canonicalize /dev/disk/by-uuid/$uuid  # it's in the df output
    cp -p $image_dir/index.gz $vault_log_dir/$uuid 2> /dev/null
  fi
}

# Iterate over all the vaults in the bank
vault_names=`extract_active_vaults`
if [ -n "$vault_names" ] ; then
  for vault in $vault_names ; do
    vault_dir=$bank_dir/$vault
    if [ ! -d $vault_dir/dirvish -o ! -r $vault_dir/dirvish/default.hist ] ; then
      echo "after-dirvish: Warning: specified Runall vault '$vault' is not valid" >&2
      continue
    fi
    process_vault $vault_dir $vault
  done
else
  # no Runall keyword, so look in the bank for vaults
  for dirvish_subdir in $bank_dir/*/dirvish ; do
    vault_dir=${dirvish_subdir%/*}
    process_vault $vault_dir ${vault_dir##*/}
  done
fi